1. Field of the Invention
This invention relates to a substrate provided with an optical waveguide through which a light signal is transmitted and a method of making such a substrate.
2. Description of the Related Art
A substrate with an optical waveguide has recently been proposed which is provided with an optical waveguide so that light signals and electric signals are simultaneously treated. For example, the prior art has proposed a construction in which an optical waveguide is provided on one of two sides of a substrate and a reflecting face serving as direction changing means and a light-sensitive element are disposed at one end side of the optical waveguide. In this construction, a light signal introduced into the optical waveguide is reflected on the reflecting face so that the direction of the light signal is changed to the light-sensitive element side. The light signal is then sensed by the light-sensitive element.
In the above-described construction, however, it is only at one side of the substrate that the light signal is transmitted. In other words, the transmitting direction of the light signal can be changed only two-dimensionally or on a plane. As a result, a region used for the light signal transmission is limited in a single substrate.